Thermal cut-out or circuit-changer.



No. 793,563. PATBNTED JUNB'27,'190-5. G. A. BROWN.

THERMAL OUT-OUT 0R CIRCUIT GHANGER.

APPLICATION FILED APR; 5. 1902. RENEWED JAN. 15.1904.

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Q Charles AEPUWU. W AtturnEHsz UNITED STATES Patented June 27, 1905.

PATENT OFFICE.

CHARLES A. BROWN, OF CHICAGO, ILLINOIS.

SPECIFICATION forming part of Letters Patent No. 793,563, dated June 27, 1905.

Application filed April 5, 1902. Renewed January 15, 1904. Serial No. 189,209.

.1") all wit/m1 it m/Ly concern;

Be it known that I, CHARLES A. BROWN, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illi-.

nois, have invented a certain new and useful Improvement in Thermal Cut-Outs or Circuit- Changers, of which the following is a full, clear, concise, and exact description, reference of an undue current the heat-responsive element, usually a mass of softenable material, is permitted to free a switching device controlled by the instrument to cause a change or break inthe circuit.

In one type of apparatus of the-prior art the heat-responsive element has been in the form of a ball or mass of softenable material, as wax, in which was contained a'heating-coil included in the circuit and which when cold was maintained in engagement with a suitable abutment by a spring, so as to relieve the wire leading to the coil within the mass of springpressure when the instrument was passive and permitting the breakage of the wire of the spring when the operating-coil was heated by an abnormal current, the spring thereupon breaking the wire. A leading objection to this class of device resided in the fact that the heating-coil would have to be repaired or replaced after each operation. Another type of thermal cut-out or circuit-changer of the prior art comprised'a structure wherein the heat-responsive element was carried upon a pin or plug included serially in the circuit to be protected. The perfect continuity of the circuit depended upon the firm and extended engagement of the pin or plug with and between the parts electrically united thereby,

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one of these parts being a spring tending to force the pin from its normal position. To secure such desired intimacy of contact, the pin had to be soldered in the position at one end, the solder constituting the softenable material responsive to heat in a coil surrounding or associated with the pin. Obviously after each operation of the device it would be diflicult to restore the pin in place to have good electric connection with the stationary terminal, and it was, moreover, necessary to restore this connection by means of a reapplication In the latter form of device, however, the wire'including the heat-concentrating coil was not ruptured, this being an advantage over the first-aforesaid prior device.

By means of my invention I am enabled to retain the advantage secured by the latter device without having the stated imperfections of either of the prior devices. To this end the heat-producing element, as acoil of wire, is relieved of that pressure which would disrupt it from the circuit, this element being maintained in the circuit against the action of the spring by means of a heat-responsive element until the presence of an abnormal current in the protected circuit, whereupon the heat-responsive mass will yield to permit thespring to operate and thereupon open or change the protected circuit. The terminals of the heat-producing element are adapted for direct electrical engagement with other terminals-that is, the heat-producing element is adapted for inclusion in the protected circuit without relying upon the conductivity of the heat-responsive element, which may thus be either metal or some insulating substance, as wax, as may be desired. In this manner the thorough inclusion of the heatproducing element in the electrical circuit is not dependent upon the heat-responsive element, but is only dependent upon the thorough connection of the terminals of the heatproducing element with terminals of the circuit, as in the case of any electrical instrument.

In the preferred embodiment of the invention the heat-producing element is in the form of a cartridge of wire having metallic end plates with which the ends of the heatingcoil are united, the metallic end plates or terminals being adapted for engagement with suitable clips or other fastening devices constituting terminals of the protected circuit, this coil being preferably fixedly mounted, the only portion of the protective device that moves being the heat responsive element. This heat-responsive element preferably ongages a spring to force the same against a normal contact to maintain continuity of the circuit, the spring being under tension serving to free itself from the normal contact when permitted so to do by the heat-responsive element when released by the action of heat in the heating-coil. The spring when thus removed from the normal contact is desirably brought into engagement with an alternate contact, so that the circuit is not only opened, but is also changed or grounded. To complete the device of my invention, the heatresponsive element or mass is caused to have plug-and-socket engagement with a metal portion, preferably a heat-conducting projection, extending from the heat-producing elemen t, whereby this heatproducing mass when heated may be removed in the operation of the device and may thereafter be replaced to restore the device to its original condition of usefulness. v

I will explain my invention more fully by reference to the accompanying drawings, in which Figure 1 is a side elevation of a device constructed in accordance with my invention, the circuit connections thereof being illustrated diagrammatically. Fig. 2 is an end view of the apparatus shown in Fig. 1. Fig. 3 is a side view of the apparatus after having responded to excessive current in the circuit. Fig. 4 is an end view of a portion of the apparatus in the direction of the arrow 4 in Fig. 3. Fig. 5 is a longitudinal sectional view of a heat-coil and associated parts constructed in accordance with the invention. Fig. 6 is a side view of one of the supports for the heatcoil, illustrating its shape before the application of the coil thereto. Fig. 7 is a view showing a modification of an element entering into my improved construction.

Like parts are indicated by similar characters of reference throughout the different fig ures.

In Fig. 1 I have diagrammatically illustrated, for example, a telephone-substation a and apparatus 7) at the exchange, included in circuit with the telephone-line. The details of the telephone-line construction are not set forth, as this will be readily understood by those skilled in the art. Moreover, my invention is obviously applicable to other systems. The circuit normally includes a heating-coil 0, which is preferably contained within a cylinder (Z, of insulating material, as hard rubber. For the purpose of the ready connection and removal of the heating-coil it may preferably be provided with end plates (2 r, which may be in the form of unwound spools, between the end pieces whereof the bifurcated ends of the terminal standardsf r may be located. One terminal of the protected circuit is thus directly connected with one terminal of the heatcoil or heat-producing element by way of the terminal 7" and the contact port-ion (2 in direct connection therewith. The other terminal of the protected circuit is preferably in the form of a loop-spring l1. and is maintained in connection with the other terminal of the heatcoil by means of an enlargement or detent Z, normally secured to the heat-coil spool. The detent is preferably entirely made of softenable material responsive to heat, as soft metal, though it need only he made in part of such softenable material to fulfil the function of the device. The detent is preferably only pressed into firm mechanical engagement with the heat-coil or the spool thereof, the spool being provided with a free end portion 1 adapted for reception within a recess in the detent. The shaft Z of the heat-coil spool is preferably made of metal, the portion 1' constituting a continuation thereof, so that heat due to the coil may travel through the shaft and the extension there to soften the substance of the detent to permit the spring /1. to move the detent :from the spool to open the circuit between its normal contact and to make con tact with the alternate contact '1!) if such contact is provided. It may be desirable to our ploy the construction illustrated in Fig. 5, where the base of the detent vi is provided with a polygonally-sided recess engaging a correspondingly-shaped end of a threaded shaft a, received within a threaded recess in the shaft 0, or, as indicated in Fig. 7, the shaft X may be integrally formed with the projection which then may be of any desired shape. in either case it will be apparent that after the spring it has been operated the detent i may readily be replaced either by effecting the removal of the shaft 01 and inserting within the shaft 6 a complete new part, comprising the parts 71 and n. in combination, or by the placement of a part vi upon the extension Zi. \Vhere the detent v is alone replaced, it may be firmly secured in position by pinching the same into engagement with the extension by a pair of pliers.

It is obvious that changes may readily be made from the embodiment of my invention illustrated without departing from the spirit of the invention, and 1 do not, therefore, wish to be limited to the precise arrangement shown; but,

Having thus described my invention, I claim as new and desire to secure by Letters Patent 1. In a thermal circuit-changer, the combination with a heat-producing element in the form of a heat-coil, of a heat-conducting member associated therewith for receiving heat produced thereby, a heat responsive mass of material not included in an electric circuit and adapted for separable engagement with said heat-conducting member, means for including the heat-producing element in circuit, and a circuit-controlling switch detained in oneoperative position near said coil by said mass when engaging said heat-conducting member and adapted to assume another operative position away from said coil upon the release of the mass from the heat-conducting member occasioned by the heat produced by abnormal current flowing through the heat element, substantiall y as described.

2. In athermal circuit-changer, the combination with a heat-producing element in the form of a heat-coil, of a projecting member associated therewith for receiving and conducting heat produced thereby, a heat-responsivemass of material not included in an electric current and adapted for separable engagement with said projecting member, means for including the heat-producing element in circuit, and a circuit-controlling switch detained in one operative position near said coil by said mass when engaging said projecting member and adapted to assume another operative position away from the coil upon the release of the mass from the projecting member occasioned by the heat produced by abnormal current flowing through the heat element, substantially as described.

3. In a thermal circuit-changer, the combination with a heat-producing element in the form of a heat-coil, of a projection of good heat-conducting material mechanically asso ciated therewith, a heat-responsive mass of material not included in an electric circuit and secured to and containing this projection, means for including the heat-producingelement in circuit, and circuit-controllingswitching means retained in one operative position by the mass and adapted to assume another operative position upon the release of the mass occasioned by the heat produced by abnormal current in the heat element, substantially as described.

4:. In a thermal circuit-changer, the combination with a heat-producing element in the form of a heat-coil, of a projection of good heat-conducting material mechanically associated therewith, a heat-responsive mass of material not included in an electric circuit and adapted for separable plug-and-socket engagement with said projection, means for including the heat-producing element in circuit, and a circuit-controlling switch retained in one operative position near said coil by the mass when engaging said projection and adapted to assume another operative position away from said coil upon the release of the mass from the projection occasioned by the heat produced by abnormal current in theheat element, substantially as described.

5. I In a thermal circuit-changer, the combi nation with a heat-producing element in the form of a heat-coil, of a rod associated with said element-for conduetingheat received thereby, a projection of good conducting material for said rod, a heat-responsive. mass of material not included in an electric circuit and adapted for engagement with this projection, means for including the heat-producing element in circuit, and circuit-controllingswitching means held in one operative position by the mass when engaging said projection and permitted to assume another operative position upon the release of the mass occasioned by heat produced by abnormal current in the heat elernentfsubstantially as described.

6. In a thermal circuit-changer, the combination with a heat-producing element in the form of a heat-coil, of a rod associated with said element for conducting heat received thereby, a projection of good conductingmaterial on said rod, a heat-responsive mass of material not included in an electric circuit and adapted to be secured to thisprojection, means for including the heat-producing element in circuit, and circuit-controllingswitching means held in one operative position by the mass when engaging said projection and permitted to assume another operative position upon the release of the mass occasioned byheat prod uced by abnormal current in the heat element, substantially as described.

7. In a thermal circuit-changer, the combination with a heat-producing element in the form of a heat-coil, of a rod associated with said element for conducting heat received thereby, a projection of good conducting material having separable engagement with said rod, a heat-responsive mass of material not included in an electric circuit and adapted to be secured to this projection, means for in cluding the heat-producing element in circuit, and circuit-changing switching means held in one operative position by the mass when engaging said projection and permitted to assume another operative position upon the re- IID lease of the mass occasioned by heat produced by abnormal current in the heat element, substantially as described.

8. In a thermal circuit-changer, the combination with a heat-producing element in the form of a heat-coil, of a rod associated with said element for conducting heat received thereby, a projection of good conducting material having separable engagement with said rod, a heat-responsive mass of material not included in an electric circuit and detachably secured to and containing this projection, means for including the heat-producing element in circuit, and a circuit-changing spring held in one operative position by the mass when engaging said projection and permitted to assume'another operative position upon 9. In a thermal circuit-changer, the combination with a heat-producing element in the shape of a heat-coil, of a rod associated with said element for conducting heat received thereby, a projection having threaded engagement with said rod, a heat-responsive mass of material not included in an electric circuit and adapted for plug-and-socket engagement with this projection, means for including the heat-producing element in circuit, and a circuit-controlling spring held in one operative position by the mass when in engagement with said projection and permitted to assume another operative position upon the release of the mass occasioned by heat produced by abnormal current in the heat element, substantially as described.

10. In a thermal circuit-changer, the combination with a heat-producing element in the shape of a coil of wire, of a rod associated with said element for conducting heat received thereby, a 1')olygonallysided projection of conducting material having threaded engagement with said rod, a heat-responsive mass of material not included in an electric circuit and recessed to engage said projection, means for including the heat-producing element in circuit, and a circuit-controlling spring held. in one operative position by the mass when in engagement with said projection, and permitted to assume another operative position upon the release of the mass occasioned by heat produced by abnormal current in the heat element, substantially as described.

11. In a thermal circuit-changer, the combination with a heat-producing element in the form of a heat-coil, of a projecting member associated therewith for receiving and conducting heat produced thereby, a heat-responsive mass of metal not included in an electric circuit and adapted for separable engagement with the end of said projecting member, means for including the heat-producing element in circuit, and circuitcontrolling switching means detained in one operative position by said mass when engaging the end. of said projection and adapted to assume another operative position upon the release of the mass from the projecting member occasioned by the heat produced by abnormal current flowing through the heat element, substantially as described.

12. In a thermal circuit-changer, the combination with a heat-producing element in the form of a heat-coil, of a rod encircled by said coil adapted for receiving the heat produced thereby, a heat-responsive mass of material not included in an electric circuit and adapted for tight engagement with said rod, means for including the heat-producing element in circuit, and circuit controlling switching means detained in one operative position by said mass when in tight engagement with said rod and adapted to assume another operative position upon the release of the mass occasioned by the heat produced by abnormal current flowing through the heat element, substan tially as described.

13. In a thermal circuit-changer, the cornbination with a heat-producing element in the form of a heat-coil, of a rod passing entirely through said heat-coil and surrounded thereby to receive the heat produced thereby, the end of said rod projecting from said coil, a heat responsive mass of material not included in an electric circuit and adapted for tight engagement with said projecting end of said rod, means for including the heat-producing element in circuit, and circuit-controllingswitching means detained in one operative position by said mass when in tight engagement with said rod and adapted to assume anotheroperative position upon the release of the mass occasioned by the heat produced by abnormal currentflowing through the heat element, sulr stantially as described.

14. In a thermal circuit-cl'ianger, the combination with a heatproducing element in the form of a heat-coil, of a metallic heat-coraluch ing rod surrounded by said coil but insulated therefrom, heat-responsive material normally rigid on said rod, and a circuit-changingspring normally held in one operative position with respect to said red by virtue of said rigid heatresponsive material, abnormal current-flow through said coil causing softening of said heat-responsive material, whereby said spring, may assume another operative position, sub stantially as described.

15. In a thermal circuit-changer, the combination with a heat-producing element in the form of a heat-coil, of metallic end plates For said coil, a metallic heat-conducting rod passing through said coil and said end plates but insulated therefrom, hcatresponsive material normally rigid on said rod, and a oi rcuit-changing spring normally held in one operative position with respect to said red by virtue of said rigid heat-responsive material, abnormal current-flow through said coil causing softening of said heat-responsive material, whereby said springs may assume another operative position, substantially as described.

16. In a thermal circuit-changer, the combination with a heat-producing element in the form of a heat-coil, of a rod surrounded by said coil for conducting heat received thereby, a heat-responsive mass of material not included in an electric circuit and adapted for separable engagement with an end ol said rod, means for including the heat-producing element in circuit, and circuit-controlling switching means held in one operative position when said heat-responsive mass engages the end ol said rod and adapted to assume another operative position upon displaccmentot' said mass from the end of said rod, substantially as described.

17. In a thermal circuit-changer, the combination with a heat-prod ucing element in the form of a heat-coil, of a rod passing entirely of the mass occasioned by the heat produced by abnormal current flowingthrough the heat element, substantially as described.

18. In a thermal circuit-changer, the combination with a heat-producing element in the form of a heat-coil, of switching means controlled thereby, a Wire rod surrounded by said coil for conducting the heat produced thereby, and heat-responsive material engaging said rod for normally maintaining said swltching means in one operative position and for releasing said switching means upon abnormal current flowing through said coil, substantially as described.

In Witness whereof I hereunto subscribe my name this 31st day of March, A. D. 1902.

CHARLES A. BROWN.

Witnesses:

GEORGE L. CRAGG, HARVEY L. HANSON. 

